In general, facilities of basic industries, which include bridges, large-scale facilities, underground facilities, and the like have been gradually enlarged and advanced to meet various demands of social members. As a result, various new technologies, new construction methods, new materials, and the like have been introduced and the need for verification of safety and the like as prerequisites for introducing the new technologies has been required. Further, the number of superannuated structures which were built several decades ago has gradually increased and there is a trend that introduction of a precision safety diagnosis technology for evaluating a current state of the structure or an instrumentation system for maintenance is accelerated.
A safety diagnosis management system of social infrastructure facilities is generally executed by performing a nondestructive inspection by an inspector having a safety inspection certificate. However, since the safety diagnosis inspection is periodically performed, the safety diagnosis inspection has problems in that it is difficult to sense damage immediately, the structure shutdowns while inspection and inspection costs including labor costs are large because the structure needs to be inspected by inspectors. Further, approximately 90% of damage of metallic structures occurs by a fatigue crack and the fatigue crack starts from a small size which is invisible to the naked eye and only when the fatigue crack reaches 80% of a total fatigue crack cycle, the fatigue crack becomes conspicuous by the existing damage sensing method. If the fatigue crack is enlarged, the cost for restoring it increases accordingly.
Korean Patent Registration No. 0784582 (registered on Dec. 4, 2007) relates to a technology regarding apparatus and method for measuring the damage of a structure using piezoelectric devices, but has a problem in that it cannot precisely sense whether a crack occurs when supplied power is low.